The following discussion of the background art is intended to facilitate an understanding of the present invention only. The discussion is not an acknowledgement or admission that any of the material referred to is or was part of the common general knowledge as at the priority date of the application.
Osseointegration is a technique which provides amputee patients with a prosthetic implant which is integrated with the skeleton of a patient. That is, an implant where there is direct contact between living bone and the surface of a load bearing implant. Osseointegration dramatically enhances bone and joint replacement surgery by providing much stronger and longer lasting implants, which in turn provides greater quality of life for amputees.
In some currently utilised osseointegration implants, a skeletally integrated implant is connected through an opening in the stump of an amputee to an external prosthetic limb. This allows direct contact to the ground, which provides greater stability, more control and minimizes energy exerted.
As there is a direct connection between the implant and the external prosthetic limb, there is no need for a patient to use a so-called “suction” prosthesis. Patients that are unable to wear a suction prosthesis for long periods of time or those confined to a wheel chair may benefit from osseointegration implants. Indeed, bilateral amputees have been able to become mobile through osseointegration.
In some other currently utilised osseointegration implants, such as for example the implants the subject of US 2014/0195002 and US 2014/0156022, part of the implant form an abutment against the cut bone with portions of the implant extending beyond outside the cut bone. In these circumstances an implant-abutment interface is formed by against the cut bone. In such a high stress region, this implant-abutment inevitably creates small gaps between the implant and the bone. These small gaps present regions within which bacteria may colonise, potentially causing inflammation and infection.
In the other currently utilised osseointegration implants mentioned above with reference to US 2014/0195002 and US 2014/0156022 there is a region of the implant extending outwardly from the implant-abutment that interfaces with the patient's soft tissue causing friction between the soft tissue and implant.
It is against this background that embodiments of the present invention have been developed.